Coal-screen



UNITED STATES PATENT OFFICE.

J .B. SMITH, OF DUNMORE, PENNSYLVANIA.

COAL-SCREEN.

Specification forming part of Letters Patent No. 57.002., dated August7, 1866.

To all whom it 'may concern:

Be it known that I, J. B. SMITH, of Dunmore, in the county of Luzerneand State of Pennsylvania, have invented certain new and usefulImprovements in Goal-Screens; and I do hereby declare..that thefollowing is a full, clear, and exact description of the same, referencebeing had to the accompanying drawings, in whichi Figure l represents`an elevation of one of the screens in question, and Fig. 2 represents avertical longitudinal section through the same.

Similar letters of reference, where they occur-in the separate figures,denote like parts of the screen in both of the drawings.

In coal-screens as at present constructed and used the coal travels overmore meshed to obviate this hitherto waste, while I attain the sameultimate separation of the coal into regulated sizes; and my invention`consists in the use of a series of smooth cylinders in connection withthe series of concentric screens of graduated mesh, so that when thecoal of each individual screen is separated from that which is to beagain separated into uniform sizes it shall not be required to travelover any meshed surface to its place of delivery, but over a smoothsurface, where it is not rubbed, ground, or abraded, or worn away byattrition, as heretofore done.

To enable others skilled in the art to make and use my invention, I willproceed to describe the same with reference to the drawings.

0n a suitable frame or support, A, I arrange a substantial shaft, B,around and on which are made a series of concentric cylindrical screens,G D E, of such graduated mesh as will separate the broken coal into suchuniform sizes as may be required, and usually termed grate,77 range oregg,77 stove,7 and chesnut.77 The inner screen, E, is the coarser meshedof the series, and retains only the larger-sized coal, all that is lessin size than its meshes dropping through into the next screen, which hasfiner meshes and retains all the place of delivery the coal that isretained in E, or that does not pass through its meshes, T

which coal is delivered at E without any further rubbing or wearing,which produces so much waste or culm. A

At or near the point b of the screen D, I connect'a smooth cylinder, D',which serves as a conveyer for that screen, and which takes and carriesout the coal retained by the screen D in a similar manner and for asimilar purpose as that above described in connection with the innerscreen, and delivers it at D".

The external screen, C, of the series need not require theconveying-cylinder, as its coal can be delivered from the end of thescreen itself, as at C', while the coal that passes through the meshesof the screen C, and which is finer than its meshes, may be retained atF. Where, however, it is necessary to carry the coal any farther than isrequired to separate the liner from that which is retained. then thesmooth conveyers should be used for such carrying, for all unnecessaryagitation of the coal over meshed surfaces, where it is rubbed, ground,and worn away, or more than is just sufficient for the separation, isinjurious and begets great waste. l

I have shown but three screens, which separate the coal into four sizes;but, of course, more or less may be used without departing fromrthegeneral characteristics of my invention, my object being to allow thecoal to pass off without agitation after it has gone through thescreening process. l

The shaft B and its screens may be rotated by any rst moving power, andby any known mechanical devices for that purpose, and, as the screensmay have to carry a heavy weight of coal, the shaft, which eventuallysustains all the weight, should be made correspondingly strong andrigid.

The screens may be supportedon the shaft by radial arms, or in any'otherwell-known way to give them sufficient firmness thereon.

The coal'to be screened and delivered into assorted sizes is fed inthrough a hopper, G, which carries it into the interior of 'the innerscreen, E, where the larger size is retained and passes out, asheretofore stated. everything smaller than itsr meshes droppingthroughinto the next screen, D, Where another separation takes place, and thepieces less than its meshes, which are finer than those of E, dropthrough, and so on.

I nd by this system of screening and conveying that from ten to fifteenper cent. less Waste or culm is produced, which, in the quantity of coalscreened annually, amounts to a Very large sum.

Having thus fully described the nature, object, and purpose of myinvention, what I claim therein as new, and desire to secure by LettersPatent, is

Gcmleinin g With aseries of graduated meshed screens a series of smoothconveyers, so that as soon as the coal is separated it shall be carriedout of the machine without any further unnecessary agitation, which onlyproduces waste, substantially as herein described.

JOHN B. SMITH.

Witnesses:

D. G. SMITH, S. G. BARKER.

